(a) Field of the Invention
This invention relates to an electric storage battery, and its manner of construction and use, and, in particular, to such a battery that can retain a charge during prolonged periods of non-use.
(b) Description of the Prior Art
Storage batteries of various constructions have long been used in a wide variety of applications for providing direct current, as needed. One common application is the providing of current for starting an automobile. Another is for the starting of various boat motors. In recent years, those concerned with providing solar-powered or wind-powered electrical systems have relied on storage batteries for electricity when the sun or wind is available only spasmodically.
When used in such applications, e.g., in the starting of the automobile, the storage battery discharges, i.e., it uses up a certain amount of its stored charge, in starting the car. Once the car has been started, however, its operation restores the battery to full charge. The battery also discharges during periods of non-use, i.e., when the car is not being operated. Ordinarily this presents no problem, as an automobile's battery is intermittently, over relatively short time spans, being discharged slightly and brought back to full charge. However, where the period of non-use of a charged storage battery is somewhat prolonged, the battery may discharge to such an extent as to be unable to perform its intended function. Car owners who have gone on vacation and left their car unused for several days have sometimes returned to a car that wouldn't start because of this very problem.
In the case of a car owner, a discharged or weak battery, while a considerable nuisance, is primarily just that, a nuisance. To a boat owner, however, a motor that won't start because of a discharged battery can present an emergency situation.
Heretofore, others have suggested a reservoir for electrolyte storage associated with the battery. In U.S. Pat. No. 851,353 which issued Apr. 23, 1907, Hite discloses a primary battery construction in which electrolyte is normally contained in a separate compartment of the battery, when the battery is not being used. As shown in Hite, the electrolyte storage compartment or reservoir is located below and interconnected with the battery cells so that electrolyte, during periods of non-use, can be discharged and returned to the reservoir by gravity. When the battery is to be next used, air is forced into the electrolyte compartment causing the electrolyte to be forced upwardly through channels in the battery construction to the battery cells. U.S. Pat. No. 944,079 also discloses an electric battery construction wherein electrolyte is forced under pressure from a reservoir therefor upwardly into a battery. As in U.S. Pat. No. 851,353, the electrolyte can be returned to its storage tank by gravity.
Although both U.S. Pat. Nos. 851,353 and 944,079 disclose the concept of maintaining electrolyte in a reservoir associated with the battery, during periods that the battery is not being used, neither patent appreciates the problem confronting me in the making of this invention. Hite (U.S. Pat. No. 851,353), as is apparently Decker (U.S. Pat. No. 944,079), is concerned with a primary battery, not a secondary or storage battery, the concern of my invention.
In U.S. Pat. No. 3,103,452 there is disclosed a delayed-activation battery in which an electrolyte reservoir is located above the battery. However, this electrolyte once introduced into the battery cells is not returned to the reservoir during periods of battery non-use.